<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="text/javascript">
        function fun(a){//fun()里面有一个隐形的参数arguments,类似java的可以变形参，object...args
            alert("a参数为：" + a);
            alert(arguments.length);
            for (var i = 0;i<arguments.length;i++){
                alert(arguments[i]);
            }
        }
        fun(1,"我爱你",true,null);
    </script>
</head>
<body>

</body>
</html>